Some wiring devices, such as light dimmers, generate substantial heat during operation. A 1000 watt light dimmer can, under certain operating conditions, generate temperatures exceeding 100.degree. C.
Electrical code requirements limit the temperatures of certain exposed wiring devices, such as dimmers. With a few exceptions, portions of dimmers that are exposed to the occupants of buildings or houses cannot exceed 60.degree. C. under normal operating conditions. Even inaccessible portions of wiring devices have temperature requirements. In order to avoid damaging the insulation on building wiring, no portion of a dimmer more than 1/4" from the main heat sink can exceed 75.degree. C. This rule protects the insulation of field wiring, which routinely comes into contact with portions of light dimmers during installation.
A particular problem relates to the heat generated at an electrical component such as a triac. This is dealt with in prior art by mounting it far from the circuit board to which it is electrically connected.
A further problem relates to the control of the temperature of the ground strap. Since the ground strap is physically connected to the main heat sink, it tends to rise too close to the heat sink temperature. Various techniques are employed to reduce the temperature of the ground strap, such as physically locating it on the opposite side of the device from the heat generating components, usually scrs or triacs, but these techniques impose design limits on the devices that are undesirable.